What happened
On April 13, 19 71, a Piper Cherokee, registration HB-OLK, was conducting a private training flight from Birrfeld to Langenthal. Following a standard circuit, the pilot attempted an approach to the Langenthal airfield but flew too low. The aircraft struck a field located just before the runway threshold, resulting in heavy damage to the airframe. There were no injuries to the pilot or the passengers, and no damage was reported to any third-party property.
The investigation
Investigators examined the flight parameters and the aircraft's mechanical condition. The pilot held a valid private pilot license, and there was no evidence of impaired health or physical incapacity at the time of the accident. Technical inspections confirmed that the aircraft's stall warning system was fully operational.
Data regarding the landing requirements showed that at a flight weight of 830 kg and an altitude of 480 m, an indicated airspeed (IAS) of 80-85 mph should have resulted in a landing roll of approximately 200 m according to the manufacturer's manual. Given that the Langenthal runway length was 550 m, a standard landing would have been well within the available distance. The investigation established that the pilot misjudged the approach, leading to an undershoot.
Findings
- The pilot failed to maintain adequate attention to the approach speed and the airspeed warning light.
- An attempt to extend the approach by adjusting the throttle was performed too late to prevent the undershoot.